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Burton, Robyn; Crabb, David P.; Smith, Nicholas D.; Glen, Fiona C.; Garway-Heath, David F.

Glaucoma and Reading Exploring the Effects of Contrast Lowering of Text

publication date
June 18, 2012
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Past research has not fully ascertained the extent to which people with glaucoma have difficulties with reading. This study measures change in reading speed when letter contrast is reduced, to test the hypothesis that patients with glaucoma are more sensitive to letter contrast than age-similar visually healthy people.



Fifty-three patients with glaucoma [mean age: 66 years (standard deviation: 9)] with bilateral visual field (VF) defects and 40 age-similar visually healthy control subjects [mean age: 69 (standard deviation: 8) years] had reading speeds measured using sets of fixed size, non-scrolling texts on a computer setup that incorporated an eye tracking device. All participants had visual acuity ≥6/9, and they underwent standard tests of visual function including Humphrey 24-2 and 10-2 VFs. Potential non-visual confounders were also tested, including cognitive ability (Middlesex Elderly Assessment of Mental Status Test) and general reading ability. Individual average raw reading speeds were calculated from 8 trials (different passages of text) at both 100% and 20% letter contrast.



Patients had an average 24-2 VF MD of −6.5 (range: 0.7 to −17.3) dB in the better eye. The overall median reduction in reading speed due to decreasing the contrast of the text in the patients was 20%, but with considerable between-individual variation (interquartile range, 8%–44%). This reduction was significantly greater (p = 0.01) than the controls [median: 11% (interquartile range, 6%–17%)]. Patients and controls had similar average performance on Middlesex Elderly Assessment of Mental Status Test (p = 0.71), a modified Burt Reading ability test (p = 0.33), and a computer-based lexical decision task (p = 0.53) and had similar self-reported day-to-day reading frequency (p = 0.12).



Average reduction in reading speed caused by a difference in letter contrast between 100% and 20% is significantly more apparent in patients with glaucoma when compared with visually healthy people with a similar age and similar cognitive/reading ability.


Vision therapy is well worth the response, time and effort. Our Son had a hard time focusing and writing neatly. After vision therapy Seth could complete a task in half the time if previously took. His abilities to focus improved greatly and so did his handwriting.

Also, he was better at listening. As a parent, we wanted learning to be fun for our Son, and vision therapy made this possible.

Amanda T.

Vision Therapy is well worth the expense, time and effort. Our son had a hard time focusing handwriting neatly. After vision therapy Seth could complete a task in half the time it previously took his abilities to focus and improved greatly and so did his handwriting.

Also, he was better at listening. As a parent you wanted learning to be fun for our son and vision therapy made this possible.

Alexa H.

Vision Therapy has given or son the tools he needs to be able to scan and read the written word more effectively and efficiently.

He love working with John and these working sessions give him the motivation to gladly work on his homework assignments.

It amazed us to see the difference in the tracking of his eyes and along a line of it's from the beginning to the end of the treatment.

Dr. McBryar , Kristen and John  are all marvelous and we would recommend them to anyone I only wish that we would have found them sooner!

Charlotte M.

Prior to coming to the institute for vision development my son complained of daily headaches. Therapy has eliminated his headaches completely. I love knowing my son is able to learn pain-free for the rest of his life because of the work that has been done over just a few weeks in this office. He he absolutely loved coming that didn't even feel like going to a doctor or therapy. We are grateful for the relief he was able to find by coming here.

Thank you!

Olivia C.

Seems much less frustrated with life

Reads non-stop and fast

Spelling abilities have been hugely improved

Seems much more confident

Thank You!!!

Kelly O.

When we first came to the practice, my son did not have huge issues, but lots of small ones- trouble with reading, sports (hitting the baseball consistently), coordination, etc- that were not easily detectable,but when put together presented issues. The staff here were all very professional and loving towards him. While I was concerned in the reading, my son was concerned with the athletic side. Seeing improvement night off the bat gave him confidence that i have nor seen in him and made him want to not only Come to therapy, but also made him want to work hard. He has surpassed his grade level and above in reading and hit his first home run this year! Thank you!!!

Alice M.
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